If you do not use the music players listed on those pages then you can get support for SPC
files in any gstreamer-based application, including
KDE 4's Phonon applications when you use the gstreamer Phonon backend. The
gstspc plugin for gstreamer was written by Chris Lee
with some work by myself. It uses the OpenSPC
library to add support for SPC files to gstreamers, and is available in the gst-plugins-bad
collection (check your favorite package manager).

Unfortunately only the x86 and x86_64 platforms are supported due to the library being coded
in assembler for speed. However, recently a different SPC library was developed by
Blargg, which uses C++ and already runs on many
different platforms. I have been able to integrate into gstreamer. Once I get a patch for it
I'll submit it to the gstreamer guys. As far as speed, it's practically identical to OpenSPC
in my testing, so maybe they should have just stuck to C/C++ from the beginning. :)

Download

Supports reading and writing the different types of tags supported by the
ID666 tag format for SNES SPC files. The format is rather limited, and has two
slightly different incarnations which I've tried to detect. The tags are
always written out in ID666 binary mode.

Limitations:

Not ported to KDE 4.

To save space (the archive is smaller than the screenshot!), I've packaged
the program using the Makefile template that I used to use for abakus and tacky. It should
be able to build and install for you if you have GNU make, but don't be
surprised if something or the other goes wrong.